With the development of mobile communication technologies and growth of network scale and number of users, users' requirements tend to be more diversified and personalized, which lays an extensive foundation for launch of various value-added services such as downloading of ring tones and Multimedia Messaging Service (MMS).
If mobile operators can fully use existing network resources to provide users with rich and diversified value-added services, they can increase their market shares and improve market competitiveness on the one hand; on the other hand, they can expand their existing user groups, fully utilize phone networks, enhance their competitive power and improve the cost-effectiveness of the whole networks.
Among value-added services, Coloring Ring Back Tone (CRBT) service is effective when a UE is called. To be specific, a UE who subscribes to this service may set and manage ring back tones in various ways, and anyone who calls this UE will hear a personalized ring back tone set by the user, instead of a monotonous beep tone. A customized ring back tone may be a piece of music or a message set by the called UE.
The CRBT service caters to the requirement of fashionable and young users for showing off their personalities. Users can indirectly treat people such as friends, lovers, customers and unwelcome ones by categories by managing tones although they are the called parties in calls. In addition to individual users, the service is also valuable to enterprises. Enterprises can add advertisements to ring back tones or play the specified ring back tones for different customers so that customers can feel the hospitality. Therefore, the CRBT service has extensive user groups.
With the development and improvement of 3G technologies, the networks provide more and more functions, which provide more convenient platforms for launch of value-added services. It is well-known that VP is an important feature of a 3G mobile communication system compared with a 2nd Generation (2G) mobile communication system. Both the Wideband Code Division Multiple Access (WCDMA) system and the Time Division Synchronous Code Division Multiple Access (TD-WDMA) system can provide the VP service based on the 64 kbps circuit switching (CS) bearer to realize simultaneous interactive transmission of audio and video.
FIG. 1 and FIG. 2 show the signaling process for a calling UE in the VP service. FIG. 2 is the subsequent process of FIG. 1. The signaling flow in FIG. 1 and FIG. 2 relates to the following network entities: User's Equipment (UE), Radio Network Subsystem (RNS), Radio Network Controller (RNC) and Core Network (CN). The protocol layers relating to these network entities include Radio Resource Control (RRC), Node-B Application Part (NBAP), ATM Adaptation Layer 2 (AAL2), Dedicated Channel—Frame Protocol (DCH-FP), Radio Link Control (RLC) and Radio Access Network Application Part (RANAP). The process includes setup of channels, exchange of related information and release of channels. The technical personnel that are familiar with this field can understand that the VP series of protocols are transparent to the CN and that related information, without being processed by the CN, is directly transferred by the CN to the UE via the serving RNC.
In the WCDMA system and the TD-SCDMA system, the CN provides UEs with two options for processing of ring back tones: playing ring back tones by Called UEs, or providing ring back tones by the CN. For the former, called UEs play ring back tones that they store according to the information elements (IEs) in the Alerting message sent from the CN; for the latter, called UEs play ring back tones provided by the CN.
In the prior technical solution, 12.2 kbps voice UEs are provided with tone files in the CN protocol framework. The CN can realize the CRBT over a 12.2 kbps voice channel.
In actual application, the following problem exists in the above solution: When the prior CRBT technology is applied in the VP service, the effects of ring back tones differ greatly and ring back images cannot be implemented.
The following analyzes reasons for this problem: The performance and quality of called UEs differ greatly and ring back tones are not uniformly customized by the network. To be specific, in the prior technical solution, the CN sets up a transparent channel for the VP service. The protocol layer of the CN does not resolve high-layer VP images or voices. Therefore, the CN cannot simply play ring back tones customized by the network over a 12.2 kbps voice channel for calling UEs. Due to the difference in processing among UEs, the ring back tones not customized by the network over the transparent channel show different playing effects on UEs. In addition, as defined in related protocols, only voice is available for the VP service, and ring back images related to ring back tones are unavailable. The CN cannot play customized ring back images for calling UEs.